Microphone and speaker structure for miniature receiver and transmitter



Feb. 28, 1967 BAKER STRUCTURE FOR MINIATURE RECEIVER AND TRANSMITTER R.H. WALKER 3,306,990 MICROPHONE AND SP Filed Jan. 13, 1964 I 36 J I 2 I I30 2 1 i I 2 22 g II "I I I W;

INVENTOR.

United States Patent 3,306,990 MICROPHONE AND SPEAKER STRUCTURE FORMINIATURE RECEIVER AND TRANSMITTER Robert H. Walker, Morton Grove, Ill.,assignor to Motorola, Inc., Franklin Park, Ill., a corporation ofIllinois Filed Jan. 13, 1964, Ser. No. 337,348 2 Claims. (Cl. 179-102)This invention relates in general to portable electronic apparatus, andin particular to a transistorized miniature radio transmitter andreceiver device.

Miniaturized electronic apparatus has come into prominent usage inrecent years, particularly in transistorized radio devices of the typeof'carrying on the person and operated from a self-contained batterypower source. The use of transistors makes it possible to provide acompact light weight transmitter and receiver powered by batteries,because of the small size and reduced operating power requirements ofthe transistor.

In a miniaturized hand held transmitter and receiver, the microphone andspeaker must be separated from each other acoustically and electricallyand must also be mounted on the unit so that they are easily used by theoperator. Because of the small size of a hand held transmitter andreceiver, the space available for mounting the speaker and microphone islimited. It is also desirable, in order that the unit may be easilyused, that the speaker and microphone receive and transmit sound fromthe same location on the housing.

Accordingly, it is an object of this invention to provide an improved,compact microphone and loudspeaker structure for a miniaturetransistorized hand held receiver and transmitter wherein the microphoneand speaker do not interfere with each other.

Another object is to provide a microphone and a speaker so positioned ina housing that the sound transmitted -by the speaker and received by themicrophone enters and leaves the housing by the same opening therein.

A feature of this invention is the provision of a miniature hand heldtransistorized transmitter and receiver with a microphone locatedconcentrically with respect to the speaker and positioned between thecone of the speaker and the housing of the transmitter and receiverunit, with the microphone being magnetically and acoustically shieldedfrom the speaker.

Another feature of the invention is the provision of a miniature handheld transmitter and receiver in which the speaker and microphone aresealed to prevent moisture from entering the transmitter and receiverhousing through the opening of the speaker and the microphone.

The invention is illustrated in the drawings, wherein:

FIG. 1 is a perspective view of a miniature hand held battery poweredtransmitter and receiver;

FIG. 2 is a cross-sectional view of the transmitter and receiver shownin FIG. 1;

FIG. 3 is another view showing the mounting of the speaker andmicrophone; and

FIG. 4 is an enlarged cross sectional view illustrating the mounting ofthe speaker and microphone in the mini-ature transmitter and receivershown in FIG. 1.

In practicing this invention a miniaturized battery powered radiotransmitting and receiving device is provided which includes a plastichousing containing the electric circuit components mounted on printedwiring boards. A speaker and microphone are concentrically mounted sothat the operator can receive and transmit through one opening in thecase. The microphone is mounted between the cone of the speaker and thehousing. A metal covering is provided to secure the microphone withinthe housing, and to shield the microphone from the speaker magnet. Sealsare provided to prevent the entrance of moisture into the housing.

receiver printed wiring Referring to the drawings; FIG. 1 is aperspective view of a miniature hand held transistorized transmitter andreceiver 20, contained in a plastic housing 21. Located on one end ofhousing 21, are the volume and on-oif control 25, squelch control 26,frequency selection switch 27, and a telescopic antenna 24. Apush-to-talk switch 23 is located on one side of housing 21. A grill 22is provided behind which are located the speaker and the microphone.

FIG. 2 is a cross-sectional view of a miniature transmitter and receiverof FIG. 1 showing the location of the components inside the unit.Battery 34 is located in the battery compartment 42 at the bottom of theunit. The board 29 and transmitter printed wiring board 30 are held inposition in plastic housing 21 between cover 31 and ledges 35. Speaker33 is mounted to grill 22.

An enlarged view of the speaker and microphone mounting structure isshown in FIG. 3, and a cross-sectional view of FIG. 3 is shown in FIG.4. Molded into grill 22 is an annular ridge 36 for speaker 33 and arectangular ridge 28 for microphone 43. Rectangular ridge 28 formicrophone 43 is concentrically located with respect to annular ridge 36between speaker cone 40 and grill 22. Microphone 43 is surrounded byresilient material 45 and 47 which isolates the same acoustically fromgrill 22 and rectangular ridge 28. Microphone 43 includes a magneticstructure and a coil which generates electrical signals in response tosound waves, and the signals are coupled to transmitter wiring board 30by wire cable 56. A metal cover 46 is held in place by screws 51inserted into rectangular ridge 28. Screws 51 force cover 46 againstresilient material 45 compressing it to secure microphone 43 withinrectangular ridge 28. Gaskets 50 and 52 are provided to seal therectangular ridge 28 and cover 46 to prevent the entrance of moisturethrough grill 22. Metal cover 46 also provides a magnetic shield toprevent interaction between the magnetic structure of microphone 43 andmagnet 41 of speaker 33.

The edge 37 of speaker 33 is secured within annular ridge 36 by dogs 55which are forced against the edge 37 by screws 54 inserted in threadedholes 48. As shown in FIG. 3 there are three holes 48 located in annularridge 36 each of which is used to secure a dog 55 to fasten speaker 33within annular ridge 3-6. Gasket 38, positioned between grill 22 andedge 37 of speaker 33 acts as a seal to prevent the entrance of moisturearound the edges of the speaker.

In operating the miniature transmitter and receiver, it is grasped bythe lower portion of case 39 and a finger is used to operatepush-to-talk switch 23. When receiving, the operator places grill 22near his car so that any sound from the speaker can be clearly heard. Intransmitting, switch 23 is depressed and the operator speaks into grill22. The sound from the speakers voice is picked up by microphone 43 andcoupled to the transmitter portion of the unit.

Thus a structure has been shown for mounting a speaker and microphone ina miniature hand held transmitter and receiver so that the sound entersand leaves from the same opening in the transmitter and receiverhousing. The speaker and microphone are isolated from each otheracoustically and magnetically and the mounting is sealed to prevent theentrance of moisture into the housing.

What I claim is:

1. Apparatus for translating sound into electrical signals and fortranslating electrical signals into sound including in combination,housing means having an apertured wall, a speaker including a cone and amagnet mounted within said housing means with said cone positionedadjacent said wall, a microphone having a magnetic structure mounted onsaid wall between said speaker cone and said wall, resilient materialmeans spacing one surface of said microphone from said wall andsubstantially surrounding the remaining surfaces of said microphone, anda cover plate of magnetic material support ing said microphone andfastened to said wall, said cover plate cooperating with said resilientmaterial means and said microphone to mechanically support saidmicrophone, to acoustically insulate said microphone from said speakerand said housing and to shield said magnetlc structure of saidmicrophone from said magnet of said speaker.

2. Apparatus for translating sound into electrical signals and fortranslating electrical signals into sound including in combination,housing means having a wall containing an opening therein, said Wallhaving an annular ridge enclosing and opening and a rectangular ridgeenclosing a portion of said opening, a speaker including a cone and amagnet mounted within said housing means, the edge of said speaker beinglocated within said annular ridge, means cooperating with said annularridge :and said edge of said speaker to fasten said speaker to saidwall, a microphone mounted partially within said rectangular ridge andbetween said speaker cone and said housing wall, first gasket meanspositioned between the edge of said speaker and said annular ridge, saidspeaker and said microphone being so mounted with respet to said openingthat sound generated by said speaker may freely leave said housing meansand that sound outside said housing means may freely enter and actuatesaid micro- 3 phone, one surface of said microphone being spaced apartfrom said wall by first resilient material means, second resilientmaterial means substantially. surrounding the remaining surfaces of saidmicrophone and spacing the same apart from said rectangular ridge, saidfirst and second resilient material means acting to acoustically isolatesaid housing means from said microphone, a cover plate of magneticmaterial fastened to said rectangular ridge, said cover platecooperating with said microphone to shield said magnetic structure ofsaid microphone from the magnetic field of said magnet, and furtheracting to compress said first and second resilient material meansagainst said microphone to secure said microphone mechanically withinsaid rectangular ridge, second gasket means positioned between saidcover plate and said rectangular ridge, said first and second gasketmeans and said, first resilient material means acting to produce a sealfor said housing means to prevent moisture from entering the circuitportion of the housing.

References Cited by the Examiner UNITED STATES PATENTS 1,196,562 8/1916Lynch 179-102 1,201,060 10/1916 Kurman 179-102 1,460,034 8/1921 Murray179-102 1,772,198 8/1930 Andersson 179-l02 2,485,405 10/1949 Olney eta1. 179-102 3,132,300 5/1964 Lefevre 325-16 JOHN W. CALDWELL, Examiner.

1. APPARATUS FOR TRANSLATING SOUND INTO ELECTRICAL SIGNALS AND FORTRANSLATING ELECTRICAL SIGNALS INTO SOUND INCLUDING IN COMBINATION,HOUSING MEANS HAVING AN APERTURED WALL, A SPEAKER INCLUDING A CONE AND AMAGNET MOUNTED WITHIN SAID HOUSING MEANS WITH SAID CONE POSITIONEDADJACENT SAID WALL, A MICROPHONE HAVING A MAGNETIC STRUCTURE MOUNTED ONSAID WALL BETWEEN SAID SPEAKER CONE AND SAID WALL, RESILIENT MATERIALMEANS SPACING ONE SURFACE OF SAID MICROPHONE FROM SAID WALL ANDSUBSTANTIALLY SURROUNDING THE REMAINING SURFACES OF SAID MICROPHONE, ANDA COVER PLATE OF MAGNETIC MATERIAL SUPPORTING SAID MICROPHONE ANDFASTENED TO SAID WALL, SAID COVER PLATE COOPERATING WITH SAID RESILIENTMATERIAL MEANS AND SAID MICROPHONE TO MECHANICALLY SUPPORT SAIDMICROPHONE, TO ACOUSTICALLY INSULATE SAID MICROPHONE FROM